Herbarium records identify the role of long-distance spread in the spatial distribution of alien plants in New Zealand

Sami Aikio, Richard Duncan, Philip Hulme

    Research output: Contribution to journalArticle

    32 Citations (Scopus)

    Abstract

    Aim To use herbarium records to characterize important correlates of spatial spread, areal occupancy and clustering of 100 alien plant species of conservation concern in the North and South Islands of New Zealand. Location New Zealand. Methods Using herbarium data of 6294 records representing 100 alien plant species, we assessed spatial heterogeneity in the distribution of alien species by examining the role of major urban areas as sources of sampling bias. A novel method to account for spatial biases in sampling effort was developed and applied to two simple distance metrics: nearest- and furthest-neighbour spread rate. The relative importance of these two distance metrics in determining the range, areal extent and dispersion of alien species across both the North and South Islands of New Zealand was also assessed. Results The spatial distribution of herbarium records was highly clustered with a significant bias towards the more populated regions. Once sampling bias was taken into account, there was no indication that species were found closer to these urban centres than might be expected based on sampling effort. The earestneighbour spread rates were usually 1–5 km yr)1 and correlated positively with the furthest-neighbour spread rates that were an order of magnitude higher. Range and area increased and clustering decreased with higher spread rates and longer recording time span. The spread rates divided species into five groups that were clearly distinguishable in terms of the extent of their istribution and the degree of clustering. Species occurring on both islands did not exhibit similar spread rates or spatial patterns. Main conclusions The nearest- and furthest-neighbour spread rates from herbarium records can explain the area and pattern of alien plant distributions and improve the understanding of the dynamics of their spread. Five groups emerge from the spread rates in relation to a null model. Fast-spreading plants had the widest, least clustered distribution, which suggests widespread chronic problems; slow-spreading plants had localized, but dense, clustered distributions, indicating acutely problematic weeds. These patterns appear robust and may be useful in predicting the future patterns of spread and in planning long-term management strategies in New Zealand.
    Original languageEnglish
    Pages (from-to)1740-1751
    Number of pages12
    JournalJournal of Biogeography
    Volume37
    DOIs
    Publication statusPublished - 2010

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    herbarium
    introduced plants
    herbaria
    spatial distribution
    sampling
    sampling bias
    introduced species
    urban areas
    planning
    weeds
    rate
    methodology
    weed
    urban area
    distribution

    Cite this

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    title = "Herbarium records identify the role of long-distance spread in the spatial distribution of alien plants in New Zealand",
    abstract = "Aim To use herbarium records to characterize important correlates of spatial spread, areal occupancy and clustering of 100 alien plant species of conservation concern in the North and South Islands of New Zealand. Location New Zealand. Methods Using herbarium data of 6294 records representing 100 alien plant species, we assessed spatial heterogeneity in the distribution of alien species by examining the role of major urban areas as sources of sampling bias. A novel method to account for spatial biases in sampling effort was developed and applied to two simple distance metrics: nearest- and furthest-neighbour spread rate. The relative importance of these two distance metrics in determining the range, areal extent and dispersion of alien species across both the North and South Islands of New Zealand was also assessed. Results The spatial distribution of herbarium records was highly clustered with a significant bias towards the more populated regions. Once sampling bias was taken into account, there was no indication that species were found closer to these urban centres than might be expected based on sampling effort. The earestneighbour spread rates were usually 1–5 km yr)1 and correlated positively with the furthest-neighbour spread rates that were an order of magnitude higher. Range and area increased and clustering decreased with higher spread rates and longer recording time span. The spread rates divided species into five groups that were clearly distinguishable in terms of the extent of their istribution and the degree of clustering. Species occurring on both islands did not exhibit similar spread rates or spatial patterns. Main conclusions The nearest- and furthest-neighbour spread rates from herbarium records can explain the area and pattern of alien plant distributions and improve the understanding of the dynamics of their spread. Five groups emerge from the spread rates in relation to a null model. Fast-spreading plants had the widest, least clustered distribution, which suggests widespread chronic problems; slow-spreading plants had localized, but dense, clustered distributions, indicating acutely problematic weeds. These patterns appear robust and may be useful in predicting the future patterns of spread and in planning long-term management strategies in New Zealand.",
    keywords = "Alien plants, exotic plants, invasion, long-distance dispersal, neighbourhood, New Zealand, null model, residence time, weeds.",
    author = "Sami Aikio and Richard Duncan and Philip Hulme",
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    language = "English",
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    Herbarium records identify the role of long-distance spread in the spatial distribution of alien plants in New Zealand. / Aikio, Sami; Duncan, Richard; Hulme, Philip.

    In: Journal of Biogeography, Vol. 37, 2010, p. 1740-1751.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Herbarium records identify the role of long-distance spread in the spatial distribution of alien plants in New Zealand

    AU - Aikio, Sami

    AU - Duncan, Richard

    AU - Hulme, Philip

    PY - 2010

    Y1 - 2010

    N2 - Aim To use herbarium records to characterize important correlates of spatial spread, areal occupancy and clustering of 100 alien plant species of conservation concern in the North and South Islands of New Zealand. Location New Zealand. Methods Using herbarium data of 6294 records representing 100 alien plant species, we assessed spatial heterogeneity in the distribution of alien species by examining the role of major urban areas as sources of sampling bias. A novel method to account for spatial biases in sampling effort was developed and applied to two simple distance metrics: nearest- and furthest-neighbour spread rate. The relative importance of these two distance metrics in determining the range, areal extent and dispersion of alien species across both the North and South Islands of New Zealand was also assessed. Results The spatial distribution of herbarium records was highly clustered with a significant bias towards the more populated regions. Once sampling bias was taken into account, there was no indication that species were found closer to these urban centres than might be expected based on sampling effort. The earestneighbour spread rates were usually 1–5 km yr)1 and correlated positively with the furthest-neighbour spread rates that were an order of magnitude higher. Range and area increased and clustering decreased with higher spread rates and longer recording time span. The spread rates divided species into five groups that were clearly distinguishable in terms of the extent of their istribution and the degree of clustering. Species occurring on both islands did not exhibit similar spread rates or spatial patterns. Main conclusions The nearest- and furthest-neighbour spread rates from herbarium records can explain the area and pattern of alien plant distributions and improve the understanding of the dynamics of their spread. Five groups emerge from the spread rates in relation to a null model. Fast-spreading plants had the widest, least clustered distribution, which suggests widespread chronic problems; slow-spreading plants had localized, but dense, clustered distributions, indicating acutely problematic weeds. These patterns appear robust and may be useful in predicting the future patterns of spread and in planning long-term management strategies in New Zealand.

    AB - Aim To use herbarium records to characterize important correlates of spatial spread, areal occupancy and clustering of 100 alien plant species of conservation concern in the North and South Islands of New Zealand. Location New Zealand. Methods Using herbarium data of 6294 records representing 100 alien plant species, we assessed spatial heterogeneity in the distribution of alien species by examining the role of major urban areas as sources of sampling bias. A novel method to account for spatial biases in sampling effort was developed and applied to two simple distance metrics: nearest- and furthest-neighbour spread rate. The relative importance of these two distance metrics in determining the range, areal extent and dispersion of alien species across both the North and South Islands of New Zealand was also assessed. Results The spatial distribution of herbarium records was highly clustered with a significant bias towards the more populated regions. Once sampling bias was taken into account, there was no indication that species were found closer to these urban centres than might be expected based on sampling effort. The earestneighbour spread rates were usually 1–5 km yr)1 and correlated positively with the furthest-neighbour spread rates that were an order of magnitude higher. Range and area increased and clustering decreased with higher spread rates and longer recording time span. The spread rates divided species into five groups that were clearly distinguishable in terms of the extent of their istribution and the degree of clustering. Species occurring on both islands did not exhibit similar spread rates or spatial patterns. Main conclusions The nearest- and furthest-neighbour spread rates from herbarium records can explain the area and pattern of alien plant distributions and improve the understanding of the dynamics of their spread. Five groups emerge from the spread rates in relation to a null model. Fast-spreading plants had the widest, least clustered distribution, which suggests widespread chronic problems; slow-spreading plants had localized, but dense, clustered distributions, indicating acutely problematic weeds. These patterns appear robust and may be useful in predicting the future patterns of spread and in planning long-term management strategies in New Zealand.

    KW - Alien plants

    KW - exotic plants

    KW - invasion

    KW - long-distance dispersal

    KW - neighbourhood

    KW - New Zealand

    KW - null model

    KW - residence time

    KW - weeds.

    U2 - 10.1111/j.1365-2699.2010.02329.x

    DO - 10.1111/j.1365-2699.2010.02329.x

    M3 - Article

    VL - 37

    SP - 1740

    EP - 1751

    JO - Journal of Biogeography

    JF - Journal of Biogeography

    SN - 0305-0270

    ER -